Depression in primary care is common, morbid, and treatable. Yet depression in elderly patients frequently goes untreated, and these patients consume more health care resources than similar patients without depression. The reasons why geriatric depression goes untreated in primary care remain unclear, although physician factors including knowledge and attitudes, patient factors, and the practice environment have all been implicated as contributing factors. The goal of the proposed research is to determine how physicians, patients and the practice environment interact to affect the diagnosis, treatment , and outcomes of geriatric depression in patients known to have symptoms of depression. We propose to link data on physician decision-making and prognosticating for individual patients with patients' clinical characteristics, outcomes, and use of health services to better understand why individual patients are chosen for treatment and which patients respond to treatment. We also propose to perform a long-term follow-up study on a panel of elderly patients to determine the stability of depressive symptoms over time, and how these symptoms contribute to patients' health services use and outcome. These studies will further our understanding of why primary care physicians apparently undertreat depression, how physicians determine who would benefit from treatment for depression, and how these practice patterns might be altered to improve outcomes for depressed elderly patients. The clinical component of this proposal involves the continuation of ongoing patient care responsibilities in general internal medicine including longitudinal primary and inpatient care, and focused patient care opportunities in geriatric primary and long-term care. The teaching component includes supervision of residents and medical students in the ambulatory and acute care settings, and didactic sessions in geriatric assessment, delirium, and dementia. The primary teaching goal of this proposal is the development of a workshop in outpatient geriatric assessment for medical residents. The goal of this workshop is to help resident physicians learn to routinely and efficiently incorporate geriatric assessment into their general medicine ambulatory care practices.